Method for determining ciliary beat frequency
A method includes steps of: determining a frame rate and a video resolution of a video; selecting N number of frames from the video; performing image denoising on the N number of frames to obtain N number of denoised images; determining a plurality of target positions that correspond to a plurality of ciliary beat patterns based on commonly-located pixels of the N number of denoised images; and for each ciliary beat pattern, determining peak values among the N number of grayscale values, and determining a ciliary beat frequency based on the peak values.
1. A method for determining a ciliary beat frequency based on a video of ciliary movement, the video containing a series of consecutive frames, the method comprising steps of:
determining a frame rate of the video and a video resolution of the video;
selecting, based on the frame rate, N number of frames from the series of consecutive frames of the video, where N is a positive integer greater than one;
performing image denoising on the N number of frames to obtain N number of denoised images, respectively, each of the N number of denoised images having a resolution equal to the video resolution;
determining a plurality of target positions that respectively correspond to a plurality of ciliary beat patterns, wherein, for every N number of commonly-located pixels respectively of the N number of denoised images, when it is determined that N number of grayscale values respectively of the N number of commonly-located pixels are not the same, a position of the N number of commonly-located pixels is determined as one of the target positions, and the N number of grayscale values of the N number of commonly-located pixels at said one of the target positions represent the respective one of the plurality of ciliary beat patterns;
for each of the ciliary beat patterns, determining peak values among the N number of grayscale values; and
for each of the ciliary beat patterns, determining a ciliary beat frequency based on the peak values thus determined.
2. The method as claimed in claim 1 , wherein the step of selecting N number of frames is to select first N number of consecutive frames of the video.
3. The method as claimed in claim 1 , wherein the step of selecting N number of frames is to select N number of consecutive frames of first X seconds of the video, where N is equal to a product of X and the frame rate.
4. The method as claimed in claim 3 , wherein the sub-step of performing image smoothing includes, for each pixel of each of the N number of frames, calculating an average of grayscale values respectively of the pixel and surrounding pixels that are located within a predetermined range of the pixel, and replacing a grayscale value of the pixel with the average of grayscale values.
5. The method as claimed in claim 1 , wherein the step of performing image denoising includes sub-steps of:
performing image smoothing on the N number of frames to respectively result in N number of smoothed images;
for every N number of commonly-located pixels respectively of the N number of smoothed images, determining a position of the N number of commonly-located pixels as a noise position when it is determined that N number of grayscale values respectively of the N number of commonly-located pixels are the same; and
for each of the N number of frames, replacing a grayscale value of a pixel corresponding to the noise position with a predetermined grayscale value.
6. The method as claimed in claim 1 , wherein the step of determining a ciliary beat frequency includes sub-steps of:
determining, for every consecutive two of the peak vales, an inter-peak time interval between the consecutive two of the peak vales;
calculating an average of the inter-peak time intervals obtained from all of the peak values; and
calculating a reciprocal of the average of the inter-peak time intervals as the ciliary beat frequency.
7. The method as claimed in claim 1 , further comprising a step of:
presenting, by a display, a heat map to illustrate a spatial distribution of the ciliary beat frequencies corresponding respectively to the target positions that are determined according to all pixels of the N number of denoised images, the heat map having a resolution equal to the video resolution,
wherein, for each of the target positions, a grayscale value of a pixel of the heat map that corresponds to the target position represents the ciliary beat frequency that corresponds to the target position.
8. The method as claimed in claim 1 , further comprising a step of:
presenting, by a display, a plot illustrating distribution of the ciliary beat frequencies corresponding respectively to the target positions that are determined according to all pixels of the N number of denoised images, wherein the plot has a horizontal axis representing the ciliary beat frequencies, and a vertical axis representing, for each of the ciliary beat frequencies, a number of those of the target positions that corresponds to the ciliary beat frequency.
9. The method as claimed in claim 8 , wherein the step of presenting a plot illustrating distribution of the ciliary beat frequencies is to present one of a histogram, a line chart, a curve chart and a scatter plot.
10. The method as claimed in claim 1 , further comprising a step of:
recording N number of grayscale values of pixels, each of which is located at the target position, respectively of the N number of frames in a matrix.